Here are some details on building tiny robots and circuits. This instructable will also cover some basic tips and techniques that are useful in building robots of any size.

For me, one of the great challenges in electronics is to see just how small a robot I can make. The beautiful thing about electronics is that the components just keep getting smaller and cheaper and more efficient at an incredibly fast pace. Imagine if automobile technology were like that. Unfortunately, mechanical systems at this time, are not advancing nearly as fast as electronics.

This leads to one of the main difficulties in building very small robots: trying to fit in a small space, the mechanical system that moves the robot. The mechanical system and batteries tend to take up most of the volume of a really small robot.

pic1 shows Mr. Cube R-16, a one cubic inch micro-sumo robot that is capable of reacting to its environment with music wire whiskers (bumper switch). It can move and explore the perimeter of a small box. It can be remote controlled using a universal TV infrared remote control that is set up for a Sony TV. It can also have its Picaxe microcontroller pre-programmed with reaction patterns. Details begin on step 1.

Step 1: Components of a One Cubic Inch Robot

Mr cube R-16, is the sixteenth robot that I have built. It is a one cubic inch robot that measures 1"x1"x1". It is capable of autonomous programmable behavior or it can be remote controlled. It is not meant to be anything that is very practical or particularly useful. It is merely a prototype and proof of concept. It is, however, useful in the sense that building a tiny robot allows you to hone your miniaturization skills for robots and other small circuits.

Building Small Robots and Circuits
Keep in mind that building as small as possible means that it may take twice as long as it would normally take to build the same circuit in a larger space. All kinds of clamps are needed to hold the small components and wires in place while soldering or gluing. A bright work light and a good magnifying headset or a fixed magnifying glass are a must.

Small Motors
It turns out that one of the biggest obstacles to making really tiny robots is the gear motor that is required. The control electronics (microcontrollers) just keep getting smaller. However, finding low rpm gear motors that are small enough is not so easy.

Mr. Cube uses tiny pager gear motors that are geared at a 25:1 ratio. At that gearing, the robot is faster than I would like and a little twitchy. To fit the space, the motors had to be offset with one wheel more forward than the other. Even with that, it moves forward, backward, and turns fine. The motors were wired on to the perfboard with 24 gauge wire that was soldered and then glued with contact cement. At the rear of the robot a 4-40 sized nylon bolt was screwed into a tapped hole underneath the bottom circuit board. This smooth plastic bolt head acts as a caster to balance the robot. You can see it in the lower right of pic 4. This gives a wheel clearance at the bottom of the robot of about 1/32".

To mount the wheels, the 3/16" plastic pulleys mounted on the motors were powered up and then, while spinning, were sanded to the right diameter. They were then inserted into a hole in a metal washer that fit inside of a nylon washer and everything was epoxied together. The wheel was then coated with two coats of Liquid Tape rubber to give it traction.

Small Batteries
Another problem with the smallest robots is finding small batteries that will last. The gear motors used require fairly high currents (90-115ma) to operate. This results in a small robot that eats batteries for breakfast. The best I could find at the time, were 3-LM44 lithium button cell batteries. The battery life in very small robots of this type, is so short, (a few minutes) that they usually cannot do anything close to practical.

There was only room for three 1.5v batteries, so they ended up powering both the motors and the Picaxe controller. Because of electrical noise which small DC motors can create, one power supply for everything, is usually not a good idea. But so far it is working fine.

The space in this one inch robot was so tight that the thickness of the 28 gauge wire insulation (from ribbon cable) turned out to be a problem. I could barely put the two halves of the robot together. I estimate that about 85% of the volume of the robot is filled with components.

The robot was so small that even an on-off switch was problematic. Eventually, I might replace the crude whiskers with infrared sensors. I have literally run out of easy to use space, so fitting anything more, without resorting to surface mount technology, would be an interesting challenge.

I like to use clamshell construction for really small robots. See Pic 2. This consists of two halves that hook together with .1" strip headers and sockets. This gives easy access to all the components, making it easier to debug the circuits or make changes.

Pic 3 shows the location of some of the major components.


2 GM15 Gear Motors- 25:1 6mm Planetary Gear Pager Motor: http://www.solarbotics.com/motors_accessories/4/

18x Picaxe microcontroller available from: http://www.hvwtech.com/products_list.asp?CatID=90&SubCatID=249&SubSubCatID=250

L293 motor controller DIP IC: http://www.mouser.com

Panasonic PNA4602M infrared detector: http://www.mouser.com

30 AWG Beldsol heat strippable (solderable) magnet wire: http://www.mouser.com

3 LM44 1.5V. Lithium button cell batteries: http://www.mouser.com

Small blue on-off switch: http://www.jameco.com

Thin solder- .015" rosin core solder: http://www.mouser.com

Resistors and a 150 uf tantalum capacitor

.1" fiberglass copper traced perfboard from: http://www.allelectronics.com/cgi-bin/item/ECS-4/455/SOLDERABLE_PERF_BOARD,_LINE_PATTERN_.html

Performix (tm) liquid tape, black-Available at Wal-Mart or http://www.thetapeworks.com/liquid-tape.htm

<p>Thats just awesome, A bluetooth controlled Mr Cube would be even better! </p>
<p>robot.rar :P</p>
Would it be beneficial to use component leads as the wires? Much thinner so it would really clear up some space on the boards.
The robot is really cool, especially how tiny it is.By the way - how about you make a sheeet metal body for it?
cool if it was remote control!!!
If you read the first part of the article, it states that it is in the introduction before step one. I quote: <br> pic1 shows Mr. Cube R-16, a one cubic inch micro-sumo robot that is capable of reacting to its environment with music wire whiskers (bumper switch). It can move and explore the perimeter of a small box. It can be remote controlled using a universal TV infrared remote control that is set up for a Sony TV. It can also have its Picaxe microcontroller pre-programmed with reaction patterns. Details begin on step 1. <br> <br>
Where can I find all the information for all the componets?
where did you get the l293 i canty find that at didgikey i only found aton of others like l293nd
You can find them on ebay for under $2 shipped. But it can take about 3 weeks because those are from china.
and the micro size solar cells are perfect Harness the power of light.<br/>For use on power models and science projects, this fuel cell runs on sunlight using silicon as its semiconductor.<br/><br/><ul class="curly"><li>Efficient, 0.8x1.6&quot; (2.4cm) cell</li><li>Delivers about 0.3-amps at 0.55VDC in full sunlight</li><br/></ul>What's in the box<br/><br/><ul class="curly"><li>Silicon solar cell 0.3-amps at 0.55VDC in full sunlight.</li><br/></ul>
30 miliamps at half a volt? We would need 4 to just power the chip, and the motors, Oh man, We would need more than would ever fit on a tiny robot...
.3 A is 300mA not 30
A great power source for this would be a tiny lithium ion rechargable battery pack. I pulled one out of an air hogs moto frenzy and it is truly tiny, about 1/8ths&quot; thick and 3/8ths&quot; long.
could you please send me the schmatic through a private message?
In the grand scheme of things, it's pointless to deny yourself throwies when you probably damage the environment far more just by commuting to work (especially if you fly regularly) or produce more toxic waste each time you throw away an old appliance like a fridge<a href="http://www.cncwm.com/products/Crystal-Vase.shtml/">crystal vase</a>,<a href="http://www.cncwm.com/Candle-Holders/">candle holders</a> or TV. So instead of getting all up in someone's face about minor occasional environmental trespasses, concern yourself more with the regular industrial-scale pollution that most of us contribute to by living in a consumer society. Do you buy products manufactured in countries with poor industrial/environmental regulations? If so, fix that before blowing throwies out of proportion.<br>
can some one send me this robot pdf manual for free.plzzzzzzzzzzzzzzzzzzz<br>no money this month.
Or you can glue on some razor blade chips and let it cut its own way in. A cheaper form of battery would be a couple of cells from a little 9V battery.
is it able to avoid obstacles? can you leave your source code for your robot on this instructable? and also, can you draw a diagram with only one power supply version for us? thanks alot
That schematic only has one power source (alll grounds go to the same place). On top of that, the author specifically mentioned that using one power supply was a bad idea (step 3)
Can you talk about sparky's tank treads - Do they work well? I'm looking to build a similar bot but I am having trouble finding small enough tracks. The cheaper the better. Thanks in advance
Really nice project! I just have a few questions, though; would you happen to know if the PICAXE 18X can use two L293 Motor Drivers, since it has 8 output pins? I've been wondering if I could use two extra motors for this kind of project. Speaking of capacitors, would I be able to use a 100uf capacitor for this project, or is there a recommended range for the capacitor used in this project? I looked at the project board for this microcontroller, and there is a capacitor, as well as a few resistors; did you use the same resistor values as the ones from the project board on your project? I've been thinking about just buying the resistors, caps, and ICs from the board instead of buying the board. Please reply, and Thanks!
in picture #7 where did you get the tracks for that robot<br /> are they custom made or did u buy them ( if so where)
instread of using the wire&nbsp; bumper switch you could get one from a computer mouse they usually have three switches that arent very big either so they dont take up much space
ok do u really need to use the magned wire over normal wire? its really expensive...
if you take apart an electric motor youll find maybe about 10 feeet iof wire from the average size
You don't have to use magnet wire, but it makes it much easier to make really small robots. Magnet wire is not expensive, you can just take apart a relay and get the magnet wire that way. Generally, the smaller the relay, the thinner the wire.
The only problem with thin wires like magnet wire is that it is very thin. The thinner the wire, the more resistance and more inductance. this makes it harder to carry sufficient current through the wire, and creates more rf noise.
oh ok gotcha. Yeah I was looking for it on digitec and it was like 50$ a spool, so the spools must have held alot of wire. Ok thanks for the reply if inget a mini robot built I'll send u some pics!
what kind of programming board (what's the name) did u use to programme the microcontroller!
do you sell/give these away?
i think they are awsome but i dont have the parts do you mebe have a kit i could get?
wht different task can i do wid dis bot ??/,cud u plz send me da programming for dis?
Lots of great ideas here. A microbot is on my list of projects, but so many ideas, so little free time! What are the sleeves you use on the motor shafts on Mr Cube Two?
Wait, if they made solar panels small enough could you use those instead of batteries?
just look at the input-output ratio the output should be 4.5 volts
To Kopolis777, solar panels may be enough to power it, but any size small enough to fit on the mini-robot wouldn't (most likely) be enough to power it... (Maybe it could recharge the batteries however....)
nah...that prob wouldnt work. 1-there are no rechargable batteries that small and 2-if u use regular batteries, they might ezplode. Now maybe someone could customly create a rechargeable battery that small...i would like to see that as an ible though...an electrical transformer could be used, but that problably wouldnt work
I've got an MP3 player, recorder, FM radio, 1GB memory storage device that is packed inside a one cubic inch package. It used a Lithium Polymer battery that is very thin and flat. Maybe one of these rechargeable batteries would do the job? <br/><br/><a rel="nofollow" href="http://kokam.com/english/product/battery_main.html">http://kokam.com/english/product/battery_main.html</a><br/><br/>Hope there's something usefull at that site for you guys.<br/>Sincerely,<br/>DIY-Guy<br/>
Ah yes, those things are surface mounted if we could surface mount this we could probably get it smaller than 2 CM
sounds like a plan to me a pcb will be required, and i already have a few layouts made on my laptop, so tell me how to wire it up , and i will see what i can do...
what plan? A surface mounted chip(aka the micro controller) could get 10 times smaller than your nail...
the smt counterpart of the microcontroller used here has a different pinout, so the pcb i mad had an smt mount dip socket like <a rel="nofollow" href="http://www.westfloridacomponents.com/S029/8+Pin+IC+Adaptor+DIP+to+Surface+Mount+Socket.html">here</a> , but for 18dip then its surface mount still, but still big enough to solder<br/><br/>btw yes smt chips do get that small, but check out the sparkfun tutorials on smt soldering and maybe u will reconsider thinking that surface mount soldering is that difficult... <br/>
I'll tell you this, Its not easy, I can't see why it would be easy, With the soldering iron you could mess up the whole thing , I don't see how people do it...
with the soldering iron i agree the answer is hot air and soldering paste, instead of a $200+ rework station, i would use a hot air tip with a butane soldering iron (in the process of acquiring this, havent tried it yet but it should work
Well your on your own, I have no clue how that would come together, That's not easy stuff...
yeah its not easy but i think that its doable, and ive seen other people do this before<br/><br/>check out those sparkfun tutorials i mentioned <a rel="nofollow" href="http://www.sparkfun.com/commerce/tutorials.php">here</a> -- go to tab &quot;surface mount soldering tutorials<br/>
Why would i bother? I have no surface mounted components, no iron, No nothing, The other people do it because they have commercial machines that solders down the tiny stuff...

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Bio: I believe that the purpose of life is to learn how to do our best and not give in to the weaker way.
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